U.S. patent application number 10/619558 was filed with the patent office on 2004-05-06 for composition coextrudable with pvdf.
This patent application is currently assigned to ATOFINA. Invention is credited to Beaume, Francois, Bonnet, Anthony, Loyen, Karine, Silagy, David, Triballier, Karine.
Application Number | 20040086721 10/619558 |
Document ID | / |
Family ID | 27806688 |
Filed Date | 2004-05-06 |
United States Patent
Application |
20040086721 |
Kind Code |
A1 |
Bonnet, Anthony ; et
al. |
May 6, 2004 |
Composition coextrudable with PVDF
Abstract
A composition coextrudable with PVDF comprises in parts by
weight: 20 to 40 parts of PVDF; 40 to 60 parts of PMMA; 5 to 18
parts of an acrylic elastomer; 1 to 4 parts of a UV absorber; the
total making 100 parts. Coextruded films comprise a layer of the
above coextrudable composition directly attached to the latter; and
a PVDF-based layer comprising, as main constituents, 50 to 100
parts of PVDF per 50 to 0 parts of PMMA respectively. The PVDF
layer may be in the form of two layers: one placed against the
coextrudable layer and comprising, as main constituents, 50 to 90
parts of PVDF per 50 to 10 parts of PMMA respectively; and the
other (also called the outer layer) comprising, as main
constituents, 75 to 100 parts of PVDF per 25 to 0 parts of PMMA
respectively. The resultant products are generally applied to
substrates, e.g. as protective films.
Inventors: |
Bonnet, Anthony; (Beaumont
le Roger, FR) ; Beaume, Francois; (Bernay, FR)
; Loyen, Karine; (Pont-Audemer, FR) ; Triballier,
Karine; (Saint Eloi de Fourques, FR) ; Silagy,
David; (Evreux, FR) |
Correspondence
Address: |
MILLEN, WHITE, ZELANO & BRANIGAN, P.C.
2200 CLARENDON BLVD.
SUITE 1400
ARLINGTON
VA
22201
US
|
Assignee: |
ATOFINA
Puteaux
FR
|
Family ID: |
27806688 |
Appl. No.: |
10/619558 |
Filed: |
July 16, 2003 |
Current U.S.
Class: |
428/421 ;
428/515; 525/199; 525/222 |
Current CPC
Class: |
C08L 33/08 20130101;
Y10T 428/254 20150115; Y10T 428/3154 20150401; B32B 27/30 20130101;
Y10T 428/31909 20150401; C08L 33/12 20130101; Y10T 428/31935
20150401; Y10T 428/31931 20150401; Y10T 428/24975 20150115; C08L
51/003 20130101; B32B 27/08 20130101; Y10T 428/31928 20150401; C08L
27/16 20130101; C08L 33/12 20130101; C08L 2666/02 20130101 |
Class at
Publication: |
428/421 ;
525/199; 525/222; 428/515 |
International
Class: |
B32B 027/00; C08L
027/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 17, 2002 |
FR |
02.09024 |
Sep 27, 2002 |
FR |
02.11991 |
Claims
1. A composition comprising by weight: 20 to 40 parts of PVDF; 40
to 60 parts of PMMA; 5 to 18 parts of an acrylic elastomer; 1 to 4
parts of a UV absorber; the total making 100 parts.
2. A composition according to claim 1 in which the proportions are:
25 to 35 parts of PVDF; 45 to 55 parts of PMMA; 8 to 18 parts of an
acrylic elastomer; 2 to 3 parts of a UV absorber; the total making
100 parts.
3. A composition according to claim 1 in which the proportions are:
30 to 35 parts of PVDF; 50 to 55 parts of PMMA; 8 to 12 parts of an
acrylic elastomer; 2 to 3 parts of a UV absorber; the total making
100 parts.
4. Composition according to any one of the preceding claims, in
which the acrylic elastomer is a core-shell copolymer.
5. Composition according to claim 4, in which the core-shell
copolymer is chosen from soft/hard, hard/soft/hard and
hard/soft/semi-hard copolymers.
6. Coextruded films consisting of: a layer of the coextrudable
composition according to any one of the preceding claims directly
attached to the latter; and a PVDF-based layer comprising, as main
constituents, 50 to 100 parts of PVDF per 50 to 0 parts of PMMA
respectively.
7. Films according to claim 6, in which the PVDF-based layer
comprises, as main constituents, 70 to 100 parts of PVDF per 30 to
0 parts of PMMA respectively.
8. Films according to claim 7, in which the PVDF-based layer
comprises, as main constituents, 75 to 85 parts of PVDF per 25 to
15 parts of PMMA respectively.
9. Films according to any one of claims 6 to 8, in which the
thickness of the PVDF layer is advantageously between 2 and 50
.mu.m and that of the coextrudable composition between 10 and 100
.mu.m.
10. Coextruded films comprising, in the following order: a
coextrudable layer of the composition according to any one of
claims 1 to 5 (the adhesive layer); a layer placed against the
coextrudable layer and comprising, as main constituents, 50 to 90
parts of PVDF per 50 to 10 parts of PMMA respectively; and a layer
(also called the outer layer) comprising, as main constituents, 75
to 100 parts of PVDF per 25 to 0 parts of PMMA respectively.
11. Films according to claim 10, in which the outer layer
comprises, as main constituents, 85 to 100 parts of PVDF per 15 to
0 parts of PMMA respectively.
12. Films according to any one of claims 10 to 11, in which the
thickness of the layer of coextrudable composition is
advantageously between 10 and 100 .mu.m and that of each of the
other layers is advantageously between 2 and 50 .mu.m.
13. Substrates coated with a film according to any one of claims 6
to 12, the coextrudable composition being placed against the
substrate.
Description
[0001] PVDF (polyvinylidene fluoride) because of its very good
weatherablity, radiation resistance and chemical resistance is used
to protect articles or materials. In addition, it is appreciated
for its glossy appearance and its resistance to graffiti. This has
therefore led all kinds of substrates to be coated with a PVDF
film. However, PVDF adheres very poorly to most substrates and it
is therefore necessary to place an adhesive composition between the
PVDF and the substrate. The present invention relates to this
composition.
[0002] Advantageously, this composition is coextruded with the PVDF
in order to form a two-layer film, and then this film is attached
to the substrate, for example by hot pressing. The two-layer film
may also be placed in a mould, the PVDF layer being placed against
the wall of the mould, and then the substrate may be injected in
the melt state into the mould. It is also possible, depending on
the nature of the substrate, to coextrude the PVDF, the adhesive
composition and the substrate in order to obtain the PVDF-coated
substrate directly, with the adhesive composition being between the
PVDF and the substrate.
[0003] Patent GB 1 578 517 describes an ABS coated with a PVDF
film, a polyurethane layer possibly being placed between the PVDF
and the ABS.
[0004] Patent U.S. Pat. No. 4,226,904 describes a PMMA covered with
a PVDF film. To improve the adhesion, a PMMA solution in
dimethylformamide is deposited on the PVDF film and, after the
solvent has evaporated, the PVDF film is pressed onto the PMMA.
[0005] Patent U.S. Pat. No. 4,415,519 describes an ABS or PVC
substrate covered with a PVDF film, an adhesive being placed
between the PVDF and the substrate. This adhesive may be either
PMMA or a blend of 40% PMMA, 30% PVDF, and 30% ABS by weight, or
else a blend consisting of 30% PMMA, 40% of a polyacrylic
derivative and 30% ABS by weight.
[0006] Patent U.S. Pat. No. 4,364,886 describes an ABS or
unsaturated polyester substrate covered with a PVDF film, an
adhesive being placed between the PVDF and the substrate. This
adhesive is a blend of 30% PMMA, 40% of an acrylic elastomer and
30% ABS by weight.
[0007] Patent U.S. Pat. No. 5,242,976 describes a composition
coextrudable with PVDF in order to make it adhere to substrates.
The composition is a blend of 27 to 50% PMMA, 17.5 to 36.5% PVDF
and 25 to 47.45% of an acrylic elastomer by weight.
[0008] In all the above documents of the prior art, there is no
mentioned of UV stabilisers in the adhesive composition.
[0009] Patent EP 733 475 B1 describes PVDF-coated substrates; the
structure comprises, in succession, the substrate, an adhesive
layer, a PVDF layer made opaque to UV and to visible radiation and
a PVDF layer. The opaque PVDF layer is obtained by adding a product
chosen from metal oxides, pigments and benzophenones to the PVDF.
The examples illustrate only PVDF filled with 15% by weight of zinc
oxide.
[0010] Patent U.S. Pat. No. 5,256,472 describes two-layer films
comprising a first layer essentially consisting of PVDF and of a
minor amount of PMMA and a second layer intended to ensure adhesion
to a substrate. This adhesive layer consists by weight of 50 to 95
(preferably 70 to 90) parts of PMMA, 5 to 50 (preferably 10 to 30)
parts of PVDF and 0.1 to 15 parts of a UV absorber. It is explained
that the presence of the UV absorber is necessary because this
adhesive layer is sensitive to radiation and that if no UV absorber
is included then the adhesive is destroyed and the layer
essentially consisting of PVDF debonds from the substrate. The term
"PMMA" denotes methyl methacrylate homopolymers or methyl
methacrylate copolymers with a copolymerisable monomer and also
blends with an acrylate rubber, but without specifying the
proportions of PMMA and of rubber. It is also specified that if the
proportion of PMMA is less than 50 parts, the dispersion of the UV
absorber tends to be inadequate and evaporation or dissipation of
the UV absorber is likely to take place, such being undesireble
(column 4, lines 25-29). In addition, it has been discovered that
this exudation of absorber impairs the transparency of the films
and above all causes debonding. In addition, these films have no
mechanical strength, making them difficult to handle. It is
therefore necessary for the adhesive layer to contain an elastomer;
and, according to the teaching of U.S. Pat. No. 5,242,976 already
mentioned, this proportion must be between 25 and 47.45% as
calculated from the minimum and maximum values set forth in the
abstract and column 2, lines 6-14.
[0011] A composition coextrudable with PVDF has now been found such
that the UV stabilisers no longer exude, such that the
PVDF/coextrudable composition two-layer film has good mechanical
strength, which results in excellent adhesion of the PVDF layer to
the substrate and which is resistant to radiation.
[0012] The present invention relates to a composition suitable as
an adhesive layer coextrudable with PVDF and comprising:
[0013] 20 to 40 parts of PVDF;
[0014] 40 to 60 parts of PMMA;
[0015] 5 to 18 parts of an acrylic elastomer;
[0016] 1 to 4 parts of a UV absorber;
[0017] the total making 100 parts.
[0018] Thus, the composition of the invention on the one hand can
tolerate less than 50 parts by weight of PMMA and on the other hand
the relationship among the components is very different than the
relationships in U.S. Pat. No. 5,242,976.
[0019] The invention also relates to coextruded films
comprising:
[0020] a layer of the above coextrudable composition (also called
adhesive layer) directly attached to the latter; and
[0021] a PVDF-based layer comprising, as main constituents, 50 to
100 parts of PVDF per 50 to 0 parts of PMMA respectively (this
layer is also called for simplification "PVDF layer").
[0022] According to a second form of the invention, the PVDF layer
is in the form of two layers:
[0023] one placed against the coextrudable layer and comprising, as
main constituents, 50 to 90 parts of PVDF per 50 to 10 parts of
PMMA respectively; and
[0024] the other (also called the outer layer) comprising, as main
constituents, 75 to 100 parts of PVDF per 25 to 0 parts of PMMA
respectively.
[0025] These films possess mechanical properties sufficient to
allow them to be handled to be processed and to be used as a
coating transparent to visible light but opaque to UV
radiation.
[0026] The invention also relates to the substrates coated with
this film, the coextrudable (adhesive) composition being placed
against the substrate.
[0027] With regard to PVDF, this term denotes PVDFs, vinylidene
fluoride (VF2) homopolymers and vinylidene fluoride (VF2)
copolymers preferably containing at least 50% by weight of VF2 and
at least one other monomer copolymerisable with VF2.
Advantageously, the comonomer is fluorinated and may be chosen, for
example, from the vinyl fluoride; trifluoroethylene (VF3);
chlorotrifluoroethylene (CTFE); 1,2-difluoroethylene;
tetrafluoroethylene (TFE); hexafluoropropylene (HFP);
perfluoro(alkyl)vinyl ethers, such as perfluoro(methyl)vinyl ether
(PMVE), perfluoro(ethyl) vinyl ether (PEVE) and
perfluoro(propyl)vinyl ether (PPVE); perfluoro(1,3-dioxole);
perfluoro(2,2-dimethyl-1,3-dioxole) (PDD). Preferably, the possible
comonomer is chosen from chlorotrifluoroethylene (CTFE),
hexafluoroproylene (HFP), trifluoroethylene (VF3) and
tetrafluoroethylene (TFE).
[0028] Advantageously, the PVDF has a viscosity ranging from 100
Pa.s to 2000 Pa.s, the viscosity being measured at 230.degree. C.
at a shear rate of 100 s.sup.-1 using a capillary rheometer. This
is because these PVDFs are well suited to extrusion and to
injection moulding. Preferably, the PVDF has a viscosity ranging
from 300 Pa.s to 1200 Pa.s, the viscosity being measured at
230.degree. C. at a shear rate of 100 s.sup.-1 using a capillary
rheometer.
[0029] With regard to PMMA, this term denotes methyl methacrylate
homopolymers and copolymers containing at least 50% methyl
methacrylate by weight. As examples of comonomers, mention may be
made, for example, of alkyl(meth)acrylates, acrylonitrile,
butadiene, styrene and isoprene. Examples of alkyl(meth)acrylates
are described in Kirk-Othmer Encyclopaedia of Chemical Technology,
4.sup.th Edition in Vol. 1, pages 292-293 and in Vol. 16, pages
475-478. Advantageously, the PMMA may contain 0 to 20% and
preferably 5 to 15% of methyl acrylate and/or ethyl acrylate by
weight. The PMMA may be functionalised, that is to say it contains,
for example, acid, acid chloride, alcohol or anhydride functional
groups. These functional groups may be introduced by grafting or by
copolymerisation. Advantageously, this is an acid functional group
provided by the acrylic acid comonomer. Two neighbouring acrylic
acid functional groups may lose water to form an anhydride. The
proportion of functional groups may be between 0 and 15% by weight
of the PMMA containing the optional functional groups.
[0030] The MVI (melt volume index) of the PMMA may be between 2 and
15 cm.sup.3/10 min measured at 230.degree. C. under a load of 3.8
kg.
[0031] With regard to the acrylic elastomer, this denotes any one
of the following: Elastomers produced from monomers comprising
acrylonitrile, for example, a copolymer of acrylonitrile and at
least monomer chosen from butadiene, isoprene, alkyl (meth)acrylate
and styrene. Elastomers produced from monomers comprising
alkyl(meth)acrylates, for example, copolymers of
alkyl(meth)acrylate and at least one monomer chosen from butadiene,
isoprene, acrylonitrile and styrene, and core-shell materials.
[0032] As regards a core-shell material, this is in the form of
fine particles having an elastomer core and at least one
thermoplastic shell, the size of the particles being in general
less than 1 .mu.m and advantageously between 50 and 300 nm. The
core-shell materials, because they contain at least 2 chemically
different monomeric are referred to hereinafter as copolymers.
[0033] As an example of core materials, examples are isoprene or
butadiene homopolymers, isoprene copolymers with at most 30 mol %
of a vinyl monomer and butadiene copolymers with at most 30 mol %
of a vinyl monomer. The vinyl monomer may be styrene, an alkyl
styrene, acrylonitrile or an alkyl(meth)acrylate. Another core
family consists of homopolymers of an alkyl(meth)acrylate and
copolymers of an alkyl(meth)acrylate with at most 30 mol % of a
monomer chosen from another alkyl(meth)acrylate, and a vinyl
monomer. Advantageously, the alkyl(meth)acrylate is butyl acrylate.
The vinyl monomer may be styrene, an alkyl styrene, acrylonitrile,
butadiene or isoprene. The core of the core-shell copolymer may be
completely or partly crosslinked. All that is required is to add at
least difunctional monomers during preparation of the core, it
being possible for these monomers to be chosen from
poly(meth)acrylic esters of polyols such as butylene
di(meth)acrylate and trimethylolpropane trimethacrylate. Other
difunctional monomers are, for example, divinylbenzene,
trivinylbenzene, vinyl acrylate and vinyl methacrylate. The core
may also be crosslinked by introducing into it, by grafting or as
comonomer during polymerisation, unsaturated functional monomers
such as unsaturated carboxylic acid anhydrides, unsaturated
carboxylic acids and unsaturated epoxides. For example, mention may
be made of maleic anhydride, (meth)acrylic acid and glycidyl
methacrylate.
[0034] The shell or shells are styrene, alkyl styrene or methyl
methacrylate homopolymers or copolymers containing at least 70 mol
% of one of these monomers mentioned above and at least one
comonomer chosen from the other monomers mentioned above, another
alkyl(meth)acrylate, vinyl acetate and acrylonitrile. The shell may
be functionalised by introducing thereinto, by grafting or as
comonomer during polymerisation, unsaturated functional monomers
such as unsaturated carboxylic acid anhydrides, unsaturated
carboxylic acids and unsaturated epoxides. As examples, mention may
be made of maleic anhydride, (meth)acrylic acid and glycidyl
methacrylate. Mention may be made, for example, of core-shell
copolymers having a polystyrene core and core-shell copolymers
having a PMMA shell. There are also core-shell copolymers having
two shells, one made of polystyrene and the other on the outside
made of PMMA. Examples of copolymers and their method of
preparation are described in the following patents: U.S. Pat. No.
4,180,494, U.S. Pat. No. 3,808,180, U.S. Pat. No. 4,096,202, U.S.
Pat. No. 4,260,693, U.S. Pat. No. 3,287,443, U.S. Pat. No.
3,657,391, U.S. Pat. No. 4,299,928, U.S. Pat. No. 3,985,704 and
U.S. Pat. No. 5,773,520.
[0035] Advantageously, the core represents 70 to 90% and the shell
30 to 10% by weight of the core-shell copolymer.
[0036] As an example of a copolymer, mention may be made of that
comprises (i) of 75 to 80 parts of a core comprising at least 93
mol % of butadiene, 5 mol % of styrene and 0.5 to 1 mol % of
divinylbenzene and (ii) 25 to 20 parts of two shells essentially of
the same weight, the inner one made of polystyrene and the other
outer one made of PMMA.
[0037] As another example, mention may be made of those having a
poly(butyl acrylate) or butyl acrylate/butadiene copolymer core and
a PMMA shell.
[0038] All these core-shell copolymers are sometimes called
soft/hard copolymers because of the elastomer core.
[0039] There are also other types of core-shell copolymers such as
hard/soft/hard copolymers, that is to say they have, in this order,
a hard core, a soft shell and a hard shell. The hard parts may
comprise the polymers of the shell of the above soft/hard
copolymers and the soft part may comprise the polymers of the core
of the above soft/hard copolymers. Non-limiting examples of such
core-shell polymers comprise in order:
[0040] a core made of a methyl methacrylate/ethyl acrylate
copolymer;
[0041] a shell made of a butyl acrylate/styrene copolymer; and
[0042] a core made of a methyl methacrylate/ethyl acrylate
copolymer.
[0043] There are also other types of core-shell copolymers such as
hard (core)/soft/semi-hard copolymers. Compared with the previous
ones, the difference stems from the "semi-hard" outer shell which
comprises two shells, one being the intermediate shell and the
other the outer shell. The intermediate shell is a copolymer of
methyl methacrylate, styrene and at least one monomer chosen from
alkyl acrylates, butadiene and isoprene. The outer shell is a PMMA
homopolymer or copolymer. Non-limiting examples of such copolymers
comprise in order:
[0044] a core made of a methyl methacrylate/ethyl acrylate
copolymer;
[0045] a shell made of a butyl acrylate/styrene copolymer;
[0046] a shell made of a methyl methacrylate/butyl acrylate/styrene
copolymer; and
[0047] a shell made of a methyl methacrylate/ethyl acrylate
copolymer.
[0048] When choosing the proportions of acrylic elastomer, it is
necessary to take into account that which may already be contained
in the PMMA. This is because there are commercial grades of PMMA
called "impact" grades which contain acrylic impact modifiers,
usually of the core-shell type. These acrylic impact modifiers may
also be present in the PMMA because they were introduced during its
polymerisation or prepared simultaneously during its
polymerisation.
[0049] As regards the UV absorber, these are products known per se.
Such products are cited in U.S. Pat. No. 5,256,472. Advantageously,
benzotriazoles and benzophenones are used. As an example,
Tinuvin.RTM. 213 or Tinuvin.RTM. 109 and preferably Tinuvin.RTM.
234 from Ciba Specialty Chemicals may be used.
[0050] The composition coextrudable with PVDF advantageously
comprises:
[0051] 25 to 35 parts of PVDF;
[0052] 45 to 55 parts of PMMA;
[0053] 8 to 18 parts of an acrylic elastomer;
[0054] 2 to 3 parts of a UV absorber;
[0055] the total making 100 parts.
[0056] The composition coextrudable with PVDF preferably
comprises:
[0057] 30 to 35 parts of PVDF;
[0058] 50 to 55 parts of PMMA;
[0059] 8 to 12 parts of an acrylic elastomer;
[0060] 2 to 3 parts of a UV absorber;
[0061] the total making 100 parts.
[0062] The coextrudable composition may be prepared by melt
blending the PVDF, the PMMA and the acrylic elastomer to which the
UV absorber is added. Advantageously, conventional thermoplastic
mixers are used.
[0063] With regard to the coextruded film comprising the
coextrudable composition and the PVDF layer, the thickness of the
PVDF layer is advantageously between 2 and 50 .mu.m and that of the
coextrudable composition between 10 and 100 .mu.m.
[0064] Advantageously, the PVDF base layer comprises, as main
constituents, 70 to 100 parts of PVDF per 30 to 0 parts of PMMA
respectively and preferably 75 to 85 parts of PVDF per 25 to 15
parts of PMMA respectively.
[0065] According to a second form of the invention, the PVDF layer
is in the form of two layers: 2
[0066] one placed against the coextrudable layer and comprising, as
main constituents, 50 to 90 parts of PVDF per 50 to 10 parts of
PMMA respectively; and
[0067] the other (also called the outer layer) comprising, as main
constituents, 75 to 100 parts of PVDF per 25 to 0 parts of PMMA
respectively.
[0068] That is to say the films of the invention comprise, in the
following order:
[0069] a coextrudable layer of the composition of the invention
(the adhesive layer);
[0070] a layer placed against the coextrudable layer and
comprising, as main constituents, 50 to 90 parts of PVDF per 50 to
10 parts of PMMA respectively; and
[0071] a layer (also called the outer layer) comprising, as main
constituents, 75 to 100 parts of PVDF per 25 to 0 parts of PMMA
respectively.
[0072] The outer layer advantageously comprises, as main
constituents, 85 to 100 parts of PVDF per 15 to 0 parts of PMMA
respectively and preferably 90 to 100 parts of PVDF per 10 to 0
parts of PMMA respectively.
[0073] The thickness of the layer of coextrudable composition is
advantageously between 10 and 100 .mu.m and that of each of the
other layers is advantageously between 2 and 50 .mu.m.
[0074] The invention also relates to the substrates coated with
this film, the coextrudable composition being placed against the
substrate.
[0075] With regard to the substrate, mention may be made, by way of
example, of:
[0076] chlorinated polymers: PVC, PVC plastic, chlorinated PE;
[0077] polymers and copolymers containing styrene, such as ABS,
SAN, PS;
[0078] saturated polyesters (PET, PBT, etc.) and copolyesters or
blends, unsaturated polyester resins (SMC);
[0079] epoxy and phenolic resins;
[0080] ethylene/alkyl acrylate or ethylene/vinyl acetate copolymers
(e.g. EMA or EVA), which are functionalised or
unfunctionalised;
[0081] PAs (polyamides) and CoPAs (copolyamides), PEBA,
polyesteramides and TPU (thermoplastic polyurethane);
[0082] EVOH (ethylene/vinyl alcohol) copolymer;
[0083] aluminium, steel or mixtures of metals;
[0084] lignin-based composites;
[0085] acrylic compounds (PMMA, etc.)
[0086] glass;
[0087] PVC and PU foams.
[0088] In the above description, it is to be understood that the
examples of various components are not intended to be limiting of
the broad scope of the generically described components.
[0089] Without further elaboration, it is believed that one skilled
in the art can, using the preceding description, utilize the
present invention to its fullest extent. The following preferred
specific embodiments are, therefore, to be construed as merely
illustrative, and not limitative of the remainder of the disclosure
in any way whatsoever.
[0090] In the foregoing and in the following examples, all
temperatures are set forth uncorrected in degrees Celsius and, all
parts and percentages are by weight, unless otherwise
indicated.
[0091] The following products were used:
[0092] KYNAR.RTM. 720: a PVDF homopolymer from Atofina having an
MVI (Melt Volume Index) of 10 cm.sup.3/10 min (230.degree. C., 5
kg);
[0093] KYNAR.RTM. 740: a PVDF homopolymer from Atofina having an
MVI (Melt Volume Index) of 1.1 cm.sup.3/10 min (230.degree. C., 5
kg);
[0094] ALTUGLAS.RTM. BS8: a PMMA from Atoglas having an MVI of 4.5
cm.sup.3/10 min (230.degree. C.; 3.8 kg) in bead form containing
12% of a methyl acrylate comonomer;
[0095] ALTOGLAS.RTM. V 825 T: a PMMA from Atoglas having an MVI of
2.5 cm.sup.3/10 min (230.degree. C.; 3.8 kg);
[0096] TINUVIN.RTM. 109: a UV absorber of the benzotriazole type
sold by Ciba Specialty Chemicals;
[0097] TINUVIN.RTM. 213: a UV absorber of the (hydroxyphenyl)
benzotriazole type sold by Ciba Specialty Chemicals;
[0098] TINUVIN.RTM. 234: a UV absorber of the (hydroxyphenyl)
benzotriazole type sold by Ciba Specialty Chemicals;
[0099] D320: the abbreviation for DURASTRENGTH.RTM. D320, denoting
a soft/hard core-shell elastomer whose core is a butyl
acrylate/butadiene copolymer and whose shell is made of PMMA, 80 nm
in size, sold by CECA;
[0100] PARALOID.RTM. KM 355: denoting a soft/hard core-shell
elastomer whose core is a butyl acrylate homopolymer and whose
shell is made of PMMA, 150 nm in size, sold by Rohm and Haas.
EXAMPLE 1
According to the Invention
[0101] A two-layer film containing a layer composed of 80% KYNAR
720 PVDF and 20% ALTUGLAS BS8, 15 .mu.m in thickness, and a binder
35 .mu.m in thickness according to the following formulation: 31.8%
KYNAR 720, 51.7% ALTUGLAS BS8, 2.5% TINUVIN 234 and 15% D320, this
film having an elongation at break of 197%, a haze of 14 and, after
seven days spent in an oven, no exudation being observable. This
film has a UV absorbance sufficient for its use in outdoor
applications.
EXAMPLE 2
According to the Invention
[0102] A two-layer film containing a layer composed of 80% KYNAR
720 PVDF and 20% ALTUGLAS BS8, 15 .mu.m in thickness, and a binder
35 .mu.m in thickness according to the following formulation: 33.6%
KYNAR 740, 53.9% ALTUGLAS BS8, 2.5% TINUVIN 234 and 10% D320, this
film having an elongation at break of 210%, a haze of 11 and, after
seven days spent in an oven, no exudation being observable. This
film has a UV absorbance sufficient for its use in outdoor
applications.
EXAMPLE 3
According to the Invention
[0103] A two-layer film containing a layer composed of 80% KYNAR
740 PVDF and 20% ALTUGLAS BS8, 15 .mu.m in thickness, and a binder
35 .mu.m in thickness according to the following formulation: 33.6%
KYNAR 740, 53.9% ALTUGLAS BS8, 2.5% TINUVIN 109 and 10% D320, this
film having an elongation at break of 150%, a haze of 8 and, after
seven days spent in an oven, no exudation being observable. This
film has a UV absorbance sufficient for its use in outdoor
applications.
EXAMPLE 4
According to the Invention
[0104] A two-layer film containing a layer composed of 80% KYNAR
740 PVDF and 20% ALTUGLAS BS8, 15 .mu.m in thickness, and a binder
35 .mu.m in thickness according to the following formulation: 33.6%
KYNAR 740, 53.9% ALTUGLAS BS8, 2.5% TINUVIN 213 and 10% D320, this
film having an elongation at break of 150%, a haze of 6.5 and,
after seven days spent in an oven, no exudation being observable.
This film has a UV absorbance sufficient for its use in outdoor
applications.
EXAMPLE 5
According to the Invention
[0105] A two-layer film containing a layer composed of 80% KYNAR
740 PVDF and 20% ALTUGLAS BS8, 15 .mu.m in thickness, and a binder
35 .mu.m in thickness according to the following formulation: 33.6%
KYNAR 740, 53.9% ALTUGLAS BS8, 2.5% TINUVIN 234 and 10% D320, this
film having an elongation at break of 150%, a haze of 6.5 and,
after seven days spent in an oven, no exudation being observable.
This film has a UV absorbance sufficient for its use in outdoor
applications.
EXAMPLE 6
Comparative Example
[0106] A two-layer film containing a layer composed of 80% KYNAR
720 PVDF and 20% ALTUGLAS V825T, 15 .mu.m in thickness, and a
binder 35 .mu.m in thickness according to the following
formulation: 32.5% KYNAR 720, 32.5% ALTUGLAS V825T, 2.5% TINUVIN
234 and 32.5% PARALOID KM 355, this film having an elongation at
break of 150%, a haze of 15 and, after one day spent in an oven,
exudation being observable. This film has a UV absorbance
insufficient for its use in outdoor applications.
EXAMPLE 7
Comparative Example
[0107] A two-layer film containing a layer composed of 80% KYNAR
720 PVDF and 20% ALTUGLAS V825T, 15 .mu.m in thickness, and a
binder 35 .mu.m in thickness according to the following
formulation: 32.5% KYNAR 720, 32.5% ALTUGLAS V825T, 2.5% TINUVIN
234 and 32.5% DURASTRENGTH D320, this film having an elongation at
break of 150%, a haze of 15 and, after one day spent in an oven,
exudation being observable. This film has a UV absorbance
insufficient for its use in outdoor applications.
[0108] The preceding examples can be repeated with similar success
by substituting the generically or specifically described reactants
and/or operating conditions of this invention for those used in the
preceding examples.
[0109] The entire disclosures of all applications, patents and
publications, cited herein and of corresponding French application
No. 02.09024, filed Jul. 17, 2002, and French application No.
02.11991, filed Sep. 27, 2002 are incorporated by reference
herein.
[0110] From the foregoing description, one skilled in the art can
easily ascertain the essential characteristics of this invention
and, without departing from the spirit and scope thereof, can make
various changes and modifications of the invention to adapt it to
various usages and conditions.
* * * * *